Human hair is treated in many ways today with hair cosmetic preparations. These include, for instance, cleansing the hair with shampoos, the care and regeneration with rinses and treatments, and bleaching, coloring, and shaping the hair using dyes, tints, waving compositions, and styling preparations. In this connection, agents for modifying or nuancing the color of head hair play an important role. Apart from bleaching compositions which bring about an oxidative lightening of the hair by breaking down natural hair dyes, oxidative hair dyeing is of major importance in the field of hair color modification.
So-called oxidation dyeing agents are used for permanent, intensive colors with suitable fastness properties. Such dyeing agents customarily include oxidation dye precursors, also called developer components and coupler components. The developer components form the actual dyes under the influence of oxidizing agents or atmospheric oxygen with one another or during coupling with one or more coupler components. For natural-looking colors, it is customarily necessary to use a mixture of a relatively large number of oxidation dye precursors (designated as ODP hereafter); in many cases, direct dyes (designated as DD hereafter) are used, furthermore, for providing nuances.
In order to stabilize the dye precursors during storage and to accelerate the reaction during the oxidative application, oxidative dyeing agents mostly have an alkaline pH, which is adjusted with alkalizing agents, such as alkanolamines, ammonia, or inorganic bases.
The aforementioned oxidation dye precursors (ODP) and alkalizing agents are typically incorporated into a cosmetically suitable carrier, for example, a cream or a gel. The carrier assures a homogeneous distribution and a sufficient residence time of the oxidative dyeing agent on the hair.
Commercial oxidation dyeing agents are generally formulated in product series, which comprise a standardized carrier, which can be combined with the nuance-specific ODP combination and alkalizing agents as much as possible without limitation.
Consumers usually may obtain an indication of the hair color achievable with a hair dyeing agent from the packaging of the hair dyeing agent and/or a color chart enclosed in the packaging. It is very important for the consumer in this case that the result of the dyeing matches as accurately as possible the color indicated by the manufacturer.
Hair dyeing agents are therefore tested comprehensively and extensively in regard to the achievable color and a plurality of application properties before introduction on the market. However, these tests always consider the interactions between ODP and optionally DD and the standardized carrier only for a specific standardized carrier. The manufacturer frequently wishes to match a hair dyeing agent series selectively to the special requirements of specific consumer groups by adding suitable active or care substances to the standardized carrier. For example, the addition of one or more care substances with a repairing action would be advisable for consumers with highly damaged hair; the addition of one or more active substances that strengthen the hair structure would be advisable for consumers with fine hair.
The result, however, depends not only on the employed combination of the ODP and optionally DD, but is also particularly influenced by the ingredients of the carrier. For example, the addition of care and/or active substances to the standardized carriers can lead to a change in the absorption of the dyes, formed under the effect of the oxidizing agent, or the directly employed dyes on the keratinic fibers and thus to a greatly changed coloring result compared with the standardized carrier.
Such color differences or changed coloring results are called a “color shift” in the context of the present application. This color shift, also called dE or ΔE, can be determined colorimetrically with a colorimeter with which the colors in the L*,a*,b* color space are measured, for example, with a colorimeter from the company Datacolor, Spectraflash 450 type.
The L*,a*,b* color space is understood to be the CIELAB color space. The “L” value in this case stands for the lightness of the color (black-white axis); the higher the “L” value, the lighter the color. The “a” value stands for the red-green axis of the system; the higher this value, the more the color is shifted into red. The “b” value stands for the yellow-blue axis of the system; the higher this value, the more the color is shifted into yellow.
The color shift ΔE, therefore the color difference between two (hair) colors, for each of which an L*,a*,b* value combination was determined, is calculated according to following formula:ΔE=((Li−L0)2+(ai−a0)2+(bi−b0)2)1/2 a0, b0, and L0 are the L*, a*, and b* values for the hair strands dyed with use of the standardized carrier, whereas ai, and Li are the L*, a*, and b* values that are obtained for colors with the use of care and/or active substances in the standardized carrier. The higher the value for ΔE, the more pronounced the color difference or “color shift.” Color differences with ΔE<1 are not perceptible by the human eye. Color differences with ΔE<2 are only visible to the trained eye. Color differences with ΔE>2 are also visible to the untrained eye.
In the worst case, the addition of an additive to a standardized carrier causes a color shift, relative to the standard carrier without additives, of ΔE>2, which therefore is also visible to the untrained eye of the consumer. To avoid having to perform complicated tests with each addition of additives to the standardized carriers with respect to the achievable hair color and optionally the fastness properties, it is therefore desirable to identify the active and care substances for the hair, the addition of which causes no or at least only a minor color shift.
The object forming the basis for the present invention therefore was to provide cosmetic agents for color modification of keratinic fibers, which include one or more selected care and active substances that cause no or only a minimal color shift.
It was now found surprisingly that the addition of at least one special nonionic silicone polymer in cosmetic agents for dyeing keratinic fibers, in particular human hair, leads to improved care, in particular to a better compatibility with a simultaneously minimal color shift of ΔE<2.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.